1. Field of the Invention
The present invention relates to a roller pump, especially for heart-lung machines, wherein the roller pump possesses a pump head consisting of a pump stator and a pump rotor, a drive unit and a pump housing.
Basically, roller pumps consist of a pump head, a drive unit and a pump housing, of which, in turn, the pump head again consists of a pump stator and a pump rotor. The pump stator is an essentially cylindrical hollow chamber whose inner wall, which is designated as a pump bed, serves as a support for a hose piece or length which is inserted into the pump head and which lies against the inner wall. The pump rotor, which is rotatable about its central longitudinal axis, is arranged in the pump stator in such a manner that rollers, which are rotatably supported on a roller carrier, are rollable along the hose piece and thereby compress the hose piece. The pump stator possesses at least one opened section which is provided for the leading out of the hose, and through which the hose piece is conducted from the interior of the hollow chamber of the pump stator. In order to prevent the hose piece from wandering under the influence of the rollers of the pump rotor which are rolling therealong, at least one end of the hose piece must be fastened to the pump stator. For roller pumps with reversible running directions, it is necessary to provide for a fastening at both ends of the hose piece. The drive unit is arranged in the pump housing, which concurrently serves for the support of the pump head. Arranged within the pump housing for known roller pumps, in addition thereto, are electrical energy supply installations and control installations for the pump drive.
2. Discussion of the Prior Art
Roller pumps are utilized in the medical technology, especially in heart-lung pumps for the conveyance of blood in an artificial or simulated circulation. A portion of this circulation is the hose which is inserted into the pump head. Not only due to the occlusion of the hose, which is caused by the rollers of the roller pump, but already because of the contact with the inner wall of the hose, is the conveyance of blood by itself influenced and damaged in an undesirable manner. A goal of every utilization of blood pumps, especially for heart-lung machines, must accordingly be such that the interval of time is configured to be as short as possible during which the blood is in contact with the inner wall of the hose. Basically, this consideration leads to the concept that the inserted hose pieces must be maintained as short as possible. The known roller pumps, especially their utilization in heart-lung machines, do not support this intention. The heart-lung machine, which contains mostly a plurality of roller pumps, must in its entirety be so set up that there are obtained the shortest possible hose pieces.
However, in view of the size of a heart-lung machine, in most instances this produces undesirably lengthy hose lines, which lead to an extremely lengthy contact between the blood and the inner wall of the hose.